Investments (Details) - Schedule of cost and equity method investments (USD $) In Millions, unless otherwise specified	May 31, 2014	May 31, 2013
Cost method investments:
Cost method investments	$ 0	$ 5.0
Equity method investments:
Equity method investments	18.4	14.6
Total	18.4	19.6
UK-based Member]
Cost method investments:
Cost method investments	0	5.0
Equity method investments:
Equity method investments	18.3	14.6
Other [Member]
Equity method investments:
Equity method investments	$ 0.1	$ 0